Coldwave appliance

ABSTRACT

A coffee appliance includes a powered cooling system integrated with and matched to a hot coffee brewer, configured to cool freshly-brewed coffee by thermal contact to chill a small batch of fresh-brewed coffee in a cooled receiving vessel. The vessel has an evaporator coil to ice the beverage. The cooling system is a robust system, a phase change refrigerant compression-type system employing a positive-displacement compressor, sized in relation to its rate of thermal cooling and the temperature of the beverage and the thermal mass and conductivity of the fluid-contacting assembly, bringing hot coffee to an ice-cold temperature, 2-5° C., on demand and quickly. The fresh brewed, flash-cooled coffee has undiluted and undegraded flavor. An integrated appliance includes a coffee brewer and cooler in a single device, and a slide switch or valve allows the user to select hot or iced coffee.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit under 35U.S.C. § 120 to U.S. patent application Ser. No. 15/976,966, entitledCOLDWAVE APPLIANCE, filed May 11, 2018, which is a continuation of andclaims the benefit under 35 U.S.C. § 120 and 35 U.S.C. § 365(c) toInternational Application PCT/US2016/047249, entitled COLDWAVEAPPLIANCE, with an international filing date of Aug. 17, 2016, whichclaims the benefit of U.S. Provisional Patent Application Ser. No.62/254,993, filed Nov. 13, 2015, the entire contents of each of whichare incorporated herein by reference for all purposes.

TECHNICAL FIELD

The present invention relates to devices and equipment for preparingbeverages. It also relates to refrigeration or cooling equipment, and toan improved coffee brewing device.

SUMMARY OF THE INVENTION

The invention, referred to herein generally as the “appliance”, is abeverage device characterized by possessing a powered cooling system anda contact-cooling portion having a fluid-contacting part, such as animmersed cooling coil or a cooled fluid-bounding wall or plate (a“cooling body” or “coil”), that is cooled by the powered cooling systemand is configured or positioned to cool a hot beverage by thermalcontact therewith. The cooling system and body are matched to andoperatively coordinated with a hot beverage brewer, and the body ispositioned to quickly and effectively chill a small batch, such as anindividual cup, or in some embodiments a carafe, of freshly brewed orhot coffee that is passed into or run through the vessel, removing theheat of brewing, and bringing the beverage down to an icy temperature.The appliance will be described with reference to a coffee brewer, suchas a ‘pod-type’ or ‘k-cup’ brewer or a filter-type drip brewer,integrated as a single unit with the refrigerant/chiller assembly andconfigured so that the user may select whether the beverage output ofthe integrated brewer/chiller appliance is to be a cup of freshly brewedhot coffee, or is to be a cup of freshly brewed and flash-chilled icedcoffee. The “iced” coffee thus produced is a beverage of enhancedflavor, quickly and conveniently prepared without extended refrigerationor use of ice, and has a taste that is free of the dilution, and of theaging or oxidation, found in a conventionally-prepared iced orrefrigerator-cooled beverage.

The chiller portion is preferably chilled by a robust powered coolingsystem such as a phase change refrigerant compression-type system thatemploys a positive-displacement compressor driven by an electric motor,and it is sized, in relation to its required rate of thermal cooling andto the thermal mass and conductivity of the beverage and thefluid-contacting vessel assembly, to bring a cup, or a batch, of hotcoffee to an ice-cold temperature, for example, down to a temperature ofabout 2 to 5° C. (35-40° F.), on-demand and in a time period that iscompatible with the brew time, for example, of under about two minutes,for the single cup embodiment set for a 4-, 6-, 8- or 10-ounce cup size.Preferably a selector control portion starts the refrigerant compressorwhen the unit is turned ON, to pre-compress a phase change refrigerantor pre-cool the cooling stage so that the initial cup of brew isflash-cooled or cooled quite quickly.

When embodied in an integrated or dual temperature (selectable hot/cold)coffee device, the heating and brewing portion or ‘first stage’ mayfollow any conventional configuration, for example may include a stageor portion substantially identical to the popular “Mr. Coffee”, “Keurig”or a common bar-style Expresso brewing console. However the appliancefurther includes operative components such that the freshly brewed hotcoffee flows in a short, or integrated or switched flow path, from thefirst, brewing stage portion, through a second, chiller stage portion,to an output to provide iced coffee with fresh-brewed flavor. In oneintegrated brewer-chiller embodiment, the brewing and chilling portionsare arranged vertically, in a compact unit as upper- andlower-flow-through stages, with the chiller constructed as an evaporatorcoil suspended in a twist-on removable coffee-receiving vessel or cup.

The invention may also be embodied in a counter-top, chill-onlyappliance. The chill-only appliance may be configured with a chiller cupmounted, for example on an arm extending out from the appliance so thatby moving the appliance the chiller cup is positioned on the cup- orcarafe-shelf or support of a common domestic brewer. With such aconstruction, that is as a chill-only appliance, the chiller may besimply user-actuated with an ON switch, without specific controlcircuitry for coordination and integration with the brewer. Moregenerally, however the chill-only appliance may be a counter-topchiller, a stand-alone beverage cooler that receives a ‘cooling cup’ orremovably-positioned vessel to contain hot coffee, and the cup or vesselis held or positioned such that a refrigeration unit evaporator coilextends into the cooling cup and is surrounded by a hot beverage that isto be chilled. The cooling cup may attach by a twist-mount, bayonet ormagnetic coupling to the chiller head. In one embodiment a plurality ofmoving vanes are positioned centrally within, or around the perimeterof, the evaporator coil and are moved by a motor or gear to deflect orstir the fluid in the vessel thereby accelerating heat removal andassuring fast and uniform cooling of the beverage while operating with arelatively modest refrigeration unit and cooling elements or vessel ofmodest dimensions.

In either case, whether configured to catch the output of a hot beveragebrewer or configured as a free-standing chiller appliance, therefrigeration portion of the chiller assembly has a cooling capacity andthermal mass and cooling rate matched to a cup or serving of hot coffee,or to the hot fluid output of the conventional domestic or lunchroomcoffee brewer, for example, to a small, medium or large coffee cup size,or in some embodiments to a small carafe batch size (e.g., 20-30 ouncesize) of the brewer.

When intended as a general purpose counter-top chiller, an embodimentmay advantageously be constructed with refrigeration components, such asa compressor and condenser assembly, mounted below-the-counter,connected via flexible lines or rigid tubing, to an above-counterbeverage cooling head that includes an evaporator coil which extendsinto a removably mountable cup or vessel in which the beverage to bechilled is placed. Preferably the counter-top chiller has a smallfootprint, and may be similar to a soda fountain frappe machine; assuch, the unit may also be used to chill other beverages, such as fruitjuice, alcoholic cocktails or wine.

An embodiment of the integrated brewer-chiller appliance includes amechanical or an electrically operated valve for selectively passing abrewed beverage stream to either a direct output (e.g., to a cup for hotcoffee), or to the chilling vessel. The integrated appliance may furtherinclude control electronics that coordinate the operation of therefrigerant components with the heating/brewing cycle of the device, forexample, to initially compress the refrigerant, or to pre-cool thechiller vessel or coil; or may include power control elements that varyand/or selectively switch the refrigerant compression timing and fluidflow regimens, allowing the device to flash cool at least an initial cupof hot beverage, and/or to efficiently and effectively cool a larger,e.g., carafe-sized batch of 24, 30 or 40 ounces of hot coffee, eitherdirectly (if configured with a larger vessel or refrigeration assembly),or by successively cooling several smaller cup-sized flows at controlledtimes or intervals as the hot beverage is being brewed. The control andswitching elements may be set such that, when initially switched ON, therefrigeration components are powered; this assures that the compressor,evaporator and condenser have attained an operation-ready state when theflow of hot brewed coffee initially appears shortly after.

The invention also contemplates embodiments wherein power switching ofthe heater and of the compressor motor are effected under selectable orautomated control at offset intervals in such a way as to limit thetotal power draw to below a desired peak domestic appliance powerconsumption level, for example to under 1200, or under 900 or under 600watts. Such control may be programmed, and may additionally beresponsive to thermal sensors that detect the initial temperatures ofthe vessel, the vessel contents, and/or the brew as it cools, whilecontrolling flow valves and powering the refrigerant assembly so as toachieve fast and effective brewing and single-pass cooling withoutrequiring extended continuous or simultaneous operation of all thepower-using components, or incurring delays between the brewing and thecooling intervals. In this embodiment, the thermal mass of the coolingbody or vessel, and the cooling rate or capacity of the refrigerantsystem may be optimized to operate effectively by partially pre-chillingthe cooling body or vessel so as to brew and flash cool an initial cup,while optionally cooling the subsequent flow of coffee at a moremoderate rate as it is brewed. With this arrangement the appliance flashchills a cup of coffee, but lowers the peak or duration of highelectrical current draw by taking advantage of the time delays inherentin refrigerant compression and in thermal conduction profiles forcontact cooling of the fluid, and the characteristic delayed waterheating and hot coffee flow rate of a drip-brewing or k-cup coffeemechanism.

A presently preferred embodiment is a single cup brewer-chiller devicehaving a brewer portion which brews hot coffee, a chiller portion towhich the hot coffee may be selectively channeled to be chilled, and aflow selector or valve that either passes the hot coffee directly to anoutput port, or selectively diverts the hot coffee into the chillerportion before it passes to an output.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will be understood byreference to the figures below, taken together with the descriptionherein and the claims appended hereto, wherein:

FIG. 1 schematically illustrates functional elements and organization ofan embodiment of the Appliance and system flow for selectively brewing,or for brewing and chilling, coffee;

FIG. 2 shows idealized states of a heat transfer refrigerant on atemperature-entropy diagram of the beverage cooler;

FIGS. 3A, 3B, 3C and 3D show, by way of example, compressor, condenser,throttle valve and evaporator elements useful in a refrigerant assemblyof the chiller appliance;

FIG. 4 shows measured cooling times achieved with several mixer andcondenser variations during testing and validation of integrated chillerconstructions;

FIGS. 5A and 5B show right- and left-front perspective views of anintegrated domestic brewer/chiller appliance;

FIGS. 6A, 6B and 6C show left-rear perspective views of the appliance ofFIG. 5 illustrating integration of refrigeration elements into a coffeebrewer;

FIGS. 7A and 7B illustrate operation of hot (FIG. 7A) and cold (FIG. 7B)beverage selection mechanism; and

FIGS. 8A, 8B, 8C, and 8D further illustrate construction details of aselectable chilling cup of the appliance of FIGS. 5-7.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates functional elements and organization ofan embodiment of the present invention as an appliance for “brewing”instant iced coffee. Operation of the appliance involves brewing hotcoffee, and chilling the beverage so produced, wherein the chilling orrefrigeration components of the appliance are matched to the thermalload and brew path, being sized, positioned and operated to quicklyproduce a cup of iced coffee.

The upper portion of FIG. 1 shows the brewer stage of the appliance,which is illustrated as following a conventional domestic coffee brewerconstruction in which water is pumped from a water reservoir 11 by apump 13 into a heating chamber 12, and the heating chamber ispressurized by an air pump 14 to force heated water along a passage intoa brewer stage 15, such as a pod- or k-cup or filter cone coffee brewer,thus making hot, fresh-brewed coffee. The hot coffee so produced passesfrom the bottom of the brewer stage 15, either directly to a cup 16, orpasses into a cooling chamber 18 which cools the coffee to form an icedcoffee output. When the user has selected “hot” coffee, the brew mayfollow a flow path centrally through the cooling chamber, withoutcontacting the cooling element. Such an arrangement is discussed furtherbelow, and illustrated in FIGS. 5-8.

The lower portion of FIG. 1 schematically illustrates arrangement of therefrigeration components of the appliance, and their interface with thehot coffee brewer stage, and operation to cool an evaporator coil. Forproducing iced coffee, the refrigeration portion and the brewer portionof the appliance overlap in the cooling chamber 18, in which coffee fromthe brewer stage 15 is retained and contacts the evaporator coil duringa cooling interval. When a hot coffee output is selected, the coolingchamber is simply bypassed. As shown in FIG. 1, the refrigerationportion of the appliance may include a phase change refrigerationcompressor 21, which compresses and drives a refrigerant into acondenser 22. The condenser may be cooled by a fan or an array of fansto better dissipate the heat of condensation or compression, denotedQcond in the figure. From the condenser, the refrigerant expands througha throttle valve 23 entering the evaporator coil 24 as a further-cooledfluid. The evaporator coil 24 is positioned in the cooling chamber 18 tocool the hot coffee output of the brewer by contact, absorbing heat,denoted Qevap, from the beverage. The refrigerant then passes to anaccumulator 25 before entering the compressor 21 for the nextcompression cycle. The state of the refrigeration fluid changes at thevarious points of the refrigerant cycle in FIG. 1, starting from state 1entering the compressor, to a compressed but heated state 2 entering thecondenser, where heat is rejected to reach state 3, then expanding andcooling as it passes through the throttle valve 23 and attains state 4entering the evaporator as a cooled heat exchange medium for absorbingheat from the beverage before again returning to state 1 in theaccumulator ready for the next compression cycle.

FIG. 2 shows the Temperature-entropy diagram corresponding to states1-4, illustrating the work performed in compressing the refrigerant andin cooling the hot coffee.

By way of background and technical detail, applicant notes that thisapplication is based upon and related to the U.S. Provisional PatentApplication Ser. No. 62/254,993 filed in the United States Patent Officeon Nov. 13, 2015, cited supra and incorporated by reference herein inits entirety. That provisional filing described theory and operationalcharacteristics of prototype a domestic iced coffee appliances with arefrigerant portion matched to a brewer so as to effectively makeinstant iced coffee, and reported investigating the heat exchangeeffectiveness and the actual or characteristic beverage cooling times ofseveral configurations of cooling elements as described therein,including fluid cooling with a refrigerant compressor driving anevaporation coil or a cooled plate; and the rate of cooling of thecoffee as affected by several different fluid mixing or stirringregimens. The provisional patent application also suggested arrangementsfor a free-standing chiller, for an integrated brewer-chiller, and forimproved implementations of an iced coffee appliance modeled on asingle-portion k-cup brewer or modeled on a pitcher-size drip brewer.The reader is urged to consult the full text and disclosure of thatapplication, together with its figures, analytic models and technicalevaluations and alternative constructions, for descriptions oftechnology for effective implementation of the beverage cooler, andrelevant factors and general considerations, including theory, hardware,applications, and various test procedures or results illustratingintended and desirable embodiments and elucidation of technical factorsdefining the nature and scope, capacity and operating characteristicsachieved by or achievable in embodiments of the invention.

As relevant hereto, applicant found that chilling times of well underseveral minutes are achieved using a small (fractional horsepower, under500 watt) refrigeration compressor, and that chilling is enhanced byproviding a stirring or mixing mechanism in the cooling chamber 18 toimprove the rate of heat exchange and uniformity of cooling, and avoidthe formation of ice on the evaporator coil. These thermal calculationsand proof-of-principle experiments were performed by adapting componentswith a modified refrigeration cycle and a custom evaporator in thermalcontact with a receiving vessel or chamber sized for effective heatexchange contact with a cup or batch of hot coffee. The experimentsidentified and confirmed achievable target power usage of under about akilowatt for the combined heating and cooling requirements, andachieving cooling times under two minutes, and suitable dimensions andmaterials for components of a cup- or carafe-sized on-demand coffeechiller. The size and scale are such that embodiments of the chillerassembly may be integrated with the switching, fluid heating, andfluid-channeling components of a conventional coffee maker, and matchedto the thermal load of the coffee maker, to form an integral coffeebrewer-chiller-dispenser of enhanced performance that selectivelyprovides hot coffee or ice-cold coffee on demand in a counter-topappliance for domestic use.

As such, the dimensions, power and thermal characteristics fall in a lowrange and are engineered to collectively achieve fast and effectivecooling of the hot beverage. In addition, because the Appliance includesa compressor powering a refrigerant-based cooling cycle, in someembodiments it may also be run in a continuous, or near continuouscooling mode (for example under control to achieve or maintain aspecific operating temperature) and operated to successively cool anunlimited number of cups of hot coffee, or more slowly cool a largervolume provided over a longer time. Such an embodiment of the integratedAppliance is thus adapted for large functions or events and theinvention is not limited to typical domestic or small office lunchroomsituations.

From a high level systems view, the basic function of the device is toactively cool a small batch of a liquid rapidly, without dilution, ondemand. More specifically, for brewing a hot beverage such as tea orcoffee; the Appliance brews and then cools the beverage from “nearboiling” to “ice cold”; and cooling is effected in a short timeinterval, comparable to the brew time of a common single-servingdomestic brewer. Illustratively, a coffee cooling temperature drop ofover 150° F. is effected in an operating time of under one or twominutes. By arranging the cooling elements around the periphery of thecooling vessel, the device may be configured so that when hot coffee isdesired, a manual selector allows the brew stream to simply passcentrally through the cooling vessel, without loss of heat. Embodimentsof the integrated brew/chill Appliance may also be configured with asensor to sense the temperature of the cooled liquid and/or a controlcircuit to control coolant cycles or to divert fluid flow along separate‘hot’ or ‘chilled’ paths to a receiving cup accordingly. In someembodiments, controlling on the output temperature, or both input andoutput temperatures, the Appliance may be configured as a chiller only,and operated to chill other beverages, such as alcohol-based cocktails,from a less extreme initial temperature, e.g., from room- or wine-cellartemperature, to a chilled or near freezing temperature.

The structure of the Appliance will be best understood starting with adescription of an illustrative embodiment as a counter-top singleserving coffee cooling appliance.

From a process flow perspective, a refrigeration cycle is integratedwith a batch cooling container or receiving vessel. The refrigerantevaporator may comprise a helical coil sitting in the vessel chamber, ortube embedded in a wall of the vessel, and is positioned to remove heatfrom (i.e., to cool) the beverage in the receiving vessel. The beverageis automatically channeled into the container, or in some embodiments ispoured (by hand), and is held for the cooling duration, and is thenexited, for example, via a manually-operated spigot, via anautomatically switched valve at the bottom of the vessel, or by removingthe vessel and decanting the chilled beverage. The filling, cooling, andpour functions are preferably coordinated by a logic board whichactuates the compressor/refrigeration components and the appropriatevalves in the fluid path. A temperature sensor may detect the desiredthermal endpoint (e.g., 35° F.) and turn off the compressor, open anoutput valve, and/or initiate a new fill/cool cycle.

As shown in the lower portion of FIG. 1, refrigeration hardware mayinclude a compressor, condenser, throttle valve, and accumulator,examples of which are shown in FIGS. 3A, 3B, 3C and 3D. This hardware issimilar to that of a standard small refrigerator or a roomair-conditioner construction, but may be specifically scaled and adaptedto the task of quickly cooling a cup or batch of the hot beverage. Anevaporator is preferably provided as a custom coil fitted within thevessel, and may be a helix, a double helix or other shape, or a platecooled by refrigerant tubes, incorporated with the beverage containerfor effective cooling. A single helical coil positioned within acylindrical cooling vessel has been found to be effective. Preferably amixing mechanism is also provided to hasten heat exchange between thehot beverage and the fluid-contacting surface of the evaporator assemblyin the cooling vessel. Mixing increases the rate of heat transfer,especially at moderate or intermediate temperatures.

Two mixing mechanisms have been found to perform well—blade mixing(e.g., stirring) and bubble mixing. These may be implemented with arotary stirrer powered by a small drive extending down into the fluid,or a diaphragm-type air pump, respectively which provides a stream ofair to churn the fluid. Blade mixing (e.g., with an assembly of movingvanes) is preferred to avoid possible oxidation or flocculation effectsthat might occur from a bubble mixer with some brews. The benefits ofmixing include increasing the heat transfer coefficient; decreasing therequired surface area of the evaporator element, cooling member orvessel; and avoiding the formation of ice on the evaporator coil.

In a hot/cold coffee brewing Appliance, the coffee brew portion of theappliance can employ the construction of an existing brewer of the priorart; however the cooling technology, and the integration of the coffeecomponents with the cooling components, is believed to be new andinventive. The discussion below for FIGS. 5-8 illustrates one basicintegrated brewer/cooler device.

As a general beverage cooler, the Appliance may be implemented as astand-alone device rather than as a stage in a brewing device, to enablethe user to chill or process any beverage. However, to integrate thetechnology into a single cup brewer, preferentially with k-cups or othersingle-cup coffee product, the Appliance is preferably configured with arotary-type refrigerant compressor to achieve a suitably narrowfootprint, and with a controller card and user control buttons, switchesand fluid valves to control the refrigeration components and fluid pathsso as to augment a conventional brewing device to provide the option toserve hot coffee as usual or ice coffee that is “brewed hot, servedcold.” Applicant has found that integrating the brewing and coolingoperations in this manner results in an iced coffee product havingexceptional flavor and freshness. A simple spring-loaded valve in thebrew head may provide dependable, single-slide user operation withoutrequiring complex electronics or control circuitry.

Operation of the appliance will be understood with reference to thethermal characteristics of its basic operation, involving arefrigerant-based cooling module that cools a coffee-receiving coolingvessel and sized for counter-top operation. FIG. 1 schematicallyillustrates functional elements of an embodiment of the appliance andtheir system flow diagram, while FIG. 2 shows the correspondingidealized states (at an instant in time) on a T-s (temperature-entropy)diagram. As shown in the left side of FIG. 1, refrigerant starts as asaturated vapor in state 1 and passes through a compressor attaining acompressed state 2 or condenser pressure at a higher temperature. In thecondenser coil, the heat of compression is rejected from the refrigerantwith a heat flow Q_(cond) from the condenser into the surrounding airlowering the temperature of the compressed refrigerant at state 3. A fanor array of small fans directed at the condenser is provided in someembodiments to provide air circulation and assure sufficient heattransfer to avoid overheating of the condenser. From state 3 thecompressed refrigerant passes through a throttle valve, which regulatesflow of the cooled compressed refrigerant to a state 4 that then passesinto the evaporator coil.

As shown in FIG. 1, the evaporator coil is placed in heat exchangeposition with, or is positioned within, a beverage vessel where it coolsthe beverage by absorbing a flow of heat Q_(evap) from the beverage intothe refrigerant fluid, which expands or evaporates and passes to theaccumulator whence it again passes into the compressor stage. Thus, fromstate 4 to 1, heat is transferred in the evaporator from a hot beverageinto the refrigerant which then passes to anothercompression/refrigeration cycle. The accumulator is positioned toprevent liquid from entering the compressor. In FIG. 1, the beveragevessel is illustrated schematically on the right side of the Figure,corresponding to the output of a coffee brewer; in practice theevaporator coil may be integrated with a coffee brewing device, and thevessel may a bayonet-mount coffee-receiving cup that fits around theevaporator and causes coffee to accumulate and rise up and immerse theevaporator in hot coffee. The temperature-entropy diagram of FIG. 2illustrates states (1)-(4) described above. In practice a suitablerefrigeration assembly operating with a 300 to 500 watt motor has beenfound sufficient for effective operation of the described domesticcoffee chiller.

Hardware components or subsystems of the cooling portion may be adaptedfrom or similar to corresponding portions of common consumer productssuch as a small room air conditioner or a personal dormitory-stylerefrigerator. Typical components of this type are illustrated in FIG.3A-3D with discussion of some attributes for technical consideration.The hardware elements (compressor, condenser coil, evaporator coil) aresized and shaped to fit the overall volume, and in certain embodimentsdesigned to constitute a pleasing design or stylized shape, of acounter-top appliance. Thus, for example, the motor and compressor mayform a cylindrical functional unit about 10-12 cm in diameter by 25-30cm tall; the condenser coil may constitute a rectangular planar arrayabout 20 by 30 cm positioned on a rear face of the appliance and cooledby a fan or an array of small fan units, and the evaporator path mayconsist of a helical tube that is positioned for immersion in acup-shaped chamber or vessel that fits in a lower part of the brew/drippath and receives the hot beverage.

FIG. 3A shows several compressor options, which may include rotary (leftimage) and reciprocating (right image) compressor mechanisms. Both arepositive displacement compressors, which operate efficiently for lowrefrigerant flow applications, and both are commonly used in airconditioning and refrigeration applications. The rotary compressor mayinclude a liquid accumulator, as shown on the far left in FIG. 3A, whichassures that liquid does not enter the compressor stage. From aperformance standpoint, both compressors are sufficient, and the choiceof a compressor for incorporation in the appliance may be driven by costand layout considerations. For bread boarding and the initial thermalanalysis, a rotary-type compressor from a 5,000 BTU air conditionermanufactured by the LG corporation was employed, with a reduced-sizecondenser and evaporator configured for effective cooling andinterfacing with a single-cup brewer or manually-poured hot coffee.

The appliance is to occupy a countertop footprint similar to that of apopular domestic coffee brewer, and may, like them, include aprogrammable control chip which, may operate for setting such featuresas initiation of the coffee brewing operation, as well as operationsunique to the appliance, such as initiation of a cooling and/or apre-cooling operation of the compressor, cooling of the hot coffee, endof the cooling cycle, and, in some embodiments, automatic passage of thecooled beverage to an output port or receiving cup. The illustratedrotary compressor suggests a size and overall shape similar to adomestic coffee brewer such as a Keurig- or a CoffeeMate brewer, andthis overall look was selected for prototype construction.

Various options may be implemented for forming the condenser portion ofthe refrigerant module. FIG. 3B illustrates several possible condenserconstructions. The left side shows a tube and fin arrangement common toforced convection (fan driven) air conditioners, and the right shows anatural convection type commonly found, for example, in a low power orcontinuously-operating refrigerator. It was decided to use a forcedconvection type condenser coil to achieve a compact and inexpensivecounter-top appliance.

FIG. 3C shows several simple throttle valve constructions. The left sideshows a capillary tube, while the right side image illustrates apressure or flow reduction orifice. A variable area valve was notconsidered for the sake of cost and minimal controls, because themagnitude of the cooling task for the intended beverage size and knownstarting temperature allows clear definition of a fixed throttle valve.A capillary tube is chosen because it is less sensitive to disturbancesin the line and has been found to be effective and commonly used incomparable cooling applications such as air conditioners.

FIG. 3D illustrates several possible implementations of the evaporator.The left side shows a bare helically-shaped tube for immersion in thebeverage. The right side shows a cold plate type heat exchanger whereinintermediate material is used to provide a flat beverage interface. Theuse of a cold plate construction would increase cost and potentiallyintroduce thermal resistance, in particular relative to any air gaps(even small gaps on the order of 0.001 in) that may exist between therefrigerant line and the plate surface, while cleanability would be apotential trade-off when using an elongated or a double-helical spiralevaporator coil. However the components of brewed coffee, if they adhereto or build up on the heat exchange contact surface, constitute at worsta cosmetic, rather than a bacteriological, residue, so that performanceconsiderations of cooling efficacy make the bare coil evaporator thefirst choice for implementation of the appliance.

In embodiments of the beverage-cooling appliance, a mixing mechanism isdesirably also provided for the evaporator/cooling vessel in order toenhance heat transfer between the evaporator and the surrounding fluid,and to reduce the required surface area and therefore size, and toprevent ice formation as the fluid contacts the evaporator. Twomechanisms were considered: (1) a motor driven blade, paddle, whisk orpropeller for stirring the fluid, and (2) an air compressor drivenaerator/bubbler, which may be similar to one used in a fish tank, orcomparable in pressure to the aerator of a latte machine.

Several refrigerants were considered, including R134a and R410a. R134ais currently more commonly used in residential applications, but thefluorocarbon mixture R410a appears to result in better performance and,for environmental reasons, is likely to be phased in as the dominantplayer in residential applications. For these reasons, R410a ispresently preferred for the appliance.

Thermal modeling was performed for the process of cooling, roughlycontemplating cooling a 12 oz cup of coffee from 200° F. down to 35° F.in 2 minutes. The time averaged evaporator heat transfer from the coffeeto the refrigerant is

${\overset{.}{Q}}_{evap} = {\frac{mc_{p}\Delta T}{t} = {{> {\overset{.}{Q}}_{evap}} = {\frac{\left( {\frac{12}{16}\;{lb}\; m} \right)\left( {4200\frac{J}{{kg}\; K}} \right)\left( {{200} - {35}} \right)R}{\left( {2\min} \right)\left( \frac{60s}{\min} \right)\left( \frac{2.2{lb}m}{kg} \right)\left( \frac{{1.8}R}{K} \right)} = {1091W}}}}$

Assuming a refrigeration coefficient of performance of 3, the compressorpower is given by

${{COP} = \frac{{\overset{.}{Q}}_{evap}}{{\overset{.}{W}}_{comp}}} = {{> {\overset{.}{W}}_{comp}} = {\frac{{\overset{.}{Q}}_{evap}}{({COP})} = {\frac{\left( {1091W} \right)}{(3)} = {364W}}}}$

An energy balance gives the heat rejection in the condenser from therefrigerant to the air

{dot over (Q)} _(cond) ={dot over (Q)} _(evap) +{dot over (W)} _(comp)

=>{dot over (Q)} _(cond)=(1091 W)+(364 W)=1455 W

In terms of the heat exchanger, the evaporator heat transfer is given by

{dot over (Q)} _(evap) =U _(evap) A _(evap) ΔT _(evap)

where U_(evap) is the overall heat transfer coefficient, A_(evap) is thecoffee/heat exchanger interface surface area, and ΔT_(evap) is thetemperature difference between the coffee and the refrigerant. Assumingan overall heat transfer coefficient of 1000 W/m2/K (forced convection,water) and a temperature difference of 60 F, the heat transfer surfacearea is

${A_{evap} = \frac{{\overset{.}{Q}}_{evap}}{U_{evap}\Delta T_{evap}}}{= {{> A_{evap}} = {\frac{\left( {1091W} \right)\left( \frac{{3.2}8\;{ft}}{m} \right)^{2}}{\left( {1000\frac{W}{m^{2}K}} \right)\left( {60R} \right)\left( \frac{K}{{1.8}R} \right)} = {{0.3}5{ft}^{2}}}}}$

Similarly for the condenser, assuming 100 W/m/K (forced convection, air)and a temperature difference of 20° F.

${A_{cond} = \frac{{\overset{.}{Q}}_{cond}}{U_{cond}\Delta T_{cond}}}{= {{> A_{cond}} = {\frac{\left( {1455W} \right)\left( {\frac{{3.2}8{ft}}{m}.} \right)^{2}}{\left( {100\frac{W}{m^{2}K}} \right)\left( {20R} \right)\left( \frac{K}{1.8R} \right)} = {14{ft}^{2}}}}}$

The compressor and throttle valve can be sourced using conventionalrefrigeration part specifications for the cooling load above. Roughspecs for the compressor are: a volume flowrate of 0.5 to 1.0 cfm and apressure rise of 100 to 200 psi, depending on the refrigerant type.Rough specs for the throttle valve are: a capillary tube 0.040 to 0.050in ID and a tube length of 2 to 3 feet. The performance calculationsabove are time averaged rough estimates. Refined optimization isachieved with detailed analysis and hardware testing; however,illustratively, a brief summary of several test procedures is includedherein.

For confirmation of modeling, a 5000 BTU/hr window air conditioner(R410a) was deconstructed and substituted with a suitably-sizedevaporator heat exchanger. Performance levels were reported in theaforesaid provisional patent filing, and a decision was made to proceedwith a helical evaporator coil for initial product design. Testingfurther showed that mixing was effective to prevent ice formation on thecoil. Measurements were taken during a number of mixing runs.

FIG. 4 shows a subset of the cooling run test results for severalprototype mixer and evaporator variations. The beverage temperaturechange was roughly from 200 down to 40° F. The calculations showed thatthe condenser was oversized by a factor of about 2× for the desiredlevel of performance, and this was subsequently verified in tests. Afour blade mixer performed better than an eight-bladed one, anddiminishing returns were shown with respect to speed, illustrating thatonly a moderate speed would be needed. Interestingly, air mixing wasfound to be comparable to blade mixing, so the choice between air vsblade mixing may be considered open for final appliance product designsprovided no adverse taste or textures are introduced by aeration. Apaddle-wheel vane arrangement rotating around the coil periphery is alsodeemed suitable. The prototyping tests, using compressor, condenser,throttle valve, and accumulator hardware that are standard refrigerationcomponents, and an evaporator that, while a custom coil, was a helix ofrelatively standard shape, fully confirmed and enabled construction ofintegrated or free-standing coffee coolers with on-demand batch coolingperformance. The helical evaporator coil in a cylindrical beveragecooling vessel quickly and efficiently performed on-demand and fastcooling, while the addition of any of several different mixingmechanisms—blade mixing and bubble mixing—enhanced performance andprevented icing of the coil, demonstrating an ability to operatecontinuously on successive batch cooling tasks to handle cumulativelylarge tasks such as event catering which may require individual servingon a possibly repetitive basis. As noted above, other benefits of mixingin addition to preventing ice formation on the coil include increasingthe heat transfer coefficient and decreasing the surface arearequirements, thus removing space and weight constraints on the designand visual appearance of consoles or units embodying the appliance.

FIGS. 5A and 5B illustrate the integrated brewer/icer of the inventionas embodied in a pod brewer 50, showing perspective views from the frontright (FIG. 5A) and front left (FIG. 5B). The appliance has a controlpanel 52 which may include one or more suitably wired button switchesfor ON, OFF, COLD or STANDBY, and one or more LED status indicatorlights to report a status such as READY or BREWED. A user-filled waterreservoir 53 occupies the left side of the appliance, while the rightside consists of a pod- or filter-type brewer head 55 which notablyincludes a hot/cold selector handle 56 at the level of the pod or filter(discussed further in relation to FIGS. 7A and 7B infra, and a chillercup or vessel assembly 57 located vertically below the brew pod andabove the drip tray 60.

FIGS. 6A, 6B and 6C are perspective views from the back and left of theintegrated appliance 50 showing details of refrigerant unit integration.The condenser coil assembly 62 is mounted on a rear surface of theappliance 50 under a cover plate that serves to channel cooling airprovided by fans 63 a, 63 b (positioned in a fan tray 64 below thecondenser coil 62) through the cooling tower or air duct 65 forming arear portion of the body of the appliance. This arrangement providesdegree of thermal isolation between the refrigerant heat dissipationelements and the cooling vessel while improving the overall coolingcapacity of the small refrigeration assembly.

Returning to a front perspective view, FIGS. 7A and 7B illustratedetails of the brew basket assembly and operation with the hot/coldselector handle 56 and cooling vessel 57 of FIG. 5A. FIG. 7A shows thehot/cold selector in the HOT position, with the corresponding positionof the brew basket 71 and cooling vessel 57 shown in the lower portionof FIG. 7A. In this position, the outlet passage 72 at the bottom of thebrew basket 71 directly enters a central outlet passage 57 a of thevessel 57, allowing the hot coffee to pass without contacting theevaporator coil 80 (FIGS. 8B-8D) that is positioned circumferentiallyaround the central region, and to fall straight through into a coffeecup resting on the drip tray 60. FIG. 7B shows corresponding views whenthe selector handle 56 is moved to the right into the COLD or ICEDCOFFEE position. This motion moves the brew basket outlet passage 72 offcenter, so it is no longer aligned with the central hot coffee outlet 57a, thus causing the hot brew to flow into and fill the cooling vessel,contacting the evaporator coil and chilling the coffee.

FIGS. 8A-8D illustrate further details of the cooling vessel andevaporator coil for such operation. As shown, the evaporator coil 80fills a generally peripheral region, while the hot coffee throughpassage 57 a is located near the center and positioned to align with thebrew basket outlet 72 (FIG. 7A). As best seen in FIG. 8D, the hot bypasspassage 57 a which may have a contact valve at its top surface to closewhen not directly contacted by the brew basket outlet 72, leads into anopen bypass conduit 57 b which keeps the hot flow away from the nearbyevaporator coil and allows the hot brew to bypass the chilling cup anddrop straight through to the user's cup. However when the brew basketoutlet 72 is not aligned with the passage 57 a, 57 b the hot coffeefalls on top plate 57 c and runs off to the side or peripheral region,flowing down over the evaporator coil so that the beverage is cooled.With this arrangement, the helical evaporator coil may be positioned ina narrow or closely fitting annular region between the central body andthe outer wall of the vessel to assure speed and efficiency of cooling.As best seen in FIG. 8C, the evaporator assembly or the vessel mayfurther include a circumferentially mounted set of oblique vanes 85.These may be driven by a motor or drive gear in a paddle-wheel motion todeflect or drive the hot liquid radially through the evaporator coil toenhance the rate of cooling of the coffee pooled in the annular regionof the chilling cup surrounding the evaporator coil. Positioning thecoil in an annular vessel rather than an open cup assures a substantialdegree of immersion of the coil for effective heat transfer and coolingwithout introducing localized ice bridging or thermal non-uniformity.

While FIGS. 7 and 8 illustrate a specific arrangement of brew basket andchilling vessel passages for achieving bypass or cooling operationwithout electrically-operated valves, it will be appreciated that theillustrated manually-operated selector mechanism is readily adaptable tovarious common brew baskets of pod-, k-cup-, filter- or expresso-typecoffee machines, and further that such mechanical flow-selectors mayinstead be effected by push-button, electrically operated valve,selector, and/or pump mechanisms. Moreover mixing may, in variousembodiments be implemented by various paddle or whisk- or propeller-typestirring, or flow deflection or recirculation mechanisms in the coolingvessel to drive the coffee against the evaporator coil for fastefficient heat transfer without icing up. It will be understood by aperson skilled in the art that the layout of elements may be variedaccordingly when the cooling mechanism is to be integrated with, ormanually positioned under a hot coffee brewer of different overallshape, size or aspect.

Furthermore, architecture of the brew section may also be varied withina broad range of constructions. Thus, for example, while conventionalk-cup or pod-type or other brewers commonly have a top lid that lifts upslightly for insertion of the cup or pod, or for placement of coffee anda drip filter, brew heads of the present invention may be configuredwith a drawer mechanism that pulls forward to allow insertion of thecoffee charge, thereby reducing the required vertical clearance forcounter top operation. In a drawer-type embodiment, the hot/cold coffeepaths may also be implemented differently, for example, may correspondto different drawer positions, which operate to position the coffeecharge over different passages for direct output or diversion to theevaporator cooler. It will also be appreciated that while the embodimentof FIG. 6 generally places the heat rejection condenser on a broad backsurface of the appliance, and augments its efficiency by a forced airchanneling fan assembly, condenser positions at either side are alsofeasible, and passive airflow can suffice when an appliance is intendedfor occasional, single-cup or low volume operation rather than broaderhousehold or café use. Other variations may incorporate, start from orcoordinate with different existing brew mechanisms of the prior art, andmay substitute steam pressure for motorized pumping, electricallyoperated valves rather than the described manual selector for directingeither water or brewed coffee along different paths, and chiller vesselsdifferently positioned in relation to the brew assembly.

The invention being thus disclosed and representative embodimentsdescribed, further variations and modifications will occur to thoseskilled in the art, and all such variations and embodiments areconsidered to be encompassed in the invention, as set forth herein andthe claims appended hereto.

What is claimed is:
 1. An apparatus, comprising: a powered coolingassembly comprising a compressor, a condenser, and an evaporator forcompressing and circulating a phase change refrigerant through a helicalevaporator coil; a cooling chamber configured and arranged to receiveand retain a batch of a beverage during a cooling interval, at least aportion of the helical evaporator coil being positioned within thecooling chamber; and a mixer disposed within the cooling chamber, themixer including at least one blade configured and arranged to movewithin a central portion or around a perimeter of the helical evaporatorcoil so as to drive the beverage radially against loops of the helicalevaporator coil.
 2. The apparatus of claim 1, further comprising: abeverage brewer configured to brew hot coffee or tea; and a controlcircuit configured to control operation of the powered cooling assemblyand the beverage brewer so that the powered cooling assembly providesselective cooling localized at the evaporator while the beverage breweris brewing the hot coffee or tea and dispensing the hot coffee or teainto the cooling chamber.
 3. The apparatus of claim 1, wherein thehelical evaporator coil is shaped as a double helix.
 4. The apparatus ofclaim 1, wherein the at least one blade is configured and arranged tomove within the central portion of the helical evaporator coil.
 5. Theapparatus of claim 4, wherein the at least one blade comprises aplurality of vanes that extend vertically through at least part of thecentral portion of the helical evaporator coil.
 6. The apparatus ofclaim 1, wherein the at least one blade is configured and arranged tomove around the perimeter of the helical evaporator coil.
 7. Theapparatus of claim 6, wherein the at least one blade comprises aplurality of vanes configured and arranged to move circumferentiallyabout helical evaporator coil.
 8. The apparatus of claim 1, wherein aratio of a heat transfer surface area of the helical evaporator coil toa volume of the cooling chamber is at least 0.02916 square feet perfluid ounce.
 9. The apparatus of claim 1, wherein the mixer isconfigured to rotate the at least one blade at 290 or more revolutionsper minute.
 10. The apparatus of claim 9, wherein the mixer isconfigured to rotate the at least one blade at 440 or fewer revolutionsper minute.
 11. The apparatus of claim 1, wherein a ratio of a heattransfer surface area of the helical evaporator coil to a power consumedby the compressor is at least 0.00096 square feet per Watt.
 12. Amethod, comprising: operating a powered cooling assembly comprising acompressor, a condenser and an evaporator for compressing andcirculating a phase change refrigerant through a helical evaporatorcoil; introducing a beverage into a cooling chamber in which at least aportion of the helical evaporator coil is disposed; and operating amixer disposed within the cooling chamber so that at least one blade ofthe mixer moves within a central portion or around a perimeter of thehelical evaporator coil so as to drive the beverage radially againstloops of the helical evaporator coil.
 13. The method of claim 12,wherein the beverage comprises freshly-brewed coffee or tea.
 14. Themethod of claim 13, further comprising: controlling operation of thepowered cooling assembly and a beverage brewer so that the poweredcooling assembly provides selective cooling localized at the evaporatorwhile the beverage brewer is brewing the coffee or tea and dispensingthe coffee or tea into the cooling chamber.
 15. The method of claim 12,wherein the beverage comprises fruit juice, an alcoholic cocktail, orwine.
 16. The method of claim 12, wherein introducing the beverage intothe cooling chamber further comprises: retaining the beverage within thecooling chamber during a cooling interval so that at least a portion ofthe helical evaporator coil remains fully immersed within the beverageduring the cooling interval.
 17. The method of claim 12, wherein thehelical evaporator coil is shaped as a double helix.
 18. The method ofclaim 12, wherein operating the mixer comprises moving the at least oneblade within the central portion of the helical evaporator coil.
 19. Themethod of claim 18, wherein the at least one blade comprises a pluralityof vanes that extend vertically through at least part of the centralportion of the helical evaporator coil.
 20. The method of claim 12,wherein operating the mixer comprises moving the at least one bladearound the perimeter of the helical evaporator coil.
 21. The method ofclaim 20, wherein the at least one blade comprises a plurality of vanesconfigured and arranged to move circumferentially about helicalevaporator coil.
 22. The method of claim 12, wherein a ratio of a heattransfer surface area of the helical evaporator coil to a volume of thecooling chamber is at least 0.02916 square feet per fluid ounce.
 23. Themethod of claim 12, wherein operating the mixer comprises rotating theat least one blade at 290 or more revolutions per minute.
 24. The methodof claim 23, wherein operating the mixer comprises rotating the at leastone blade at 440 or fewer revolutions per minute.
 25. The method ofclaim 24, wherein a ratio of a heat transfer surface area of the helicalevaporator coil to a power consumed by the compressor is at least0.00096 square feet per Watt.